Integral selector switch and transfer switch unit for tapped regulating transformers



Feb. 1, 1966 A. BLEIBTREU 3,233,049

INTEGRAL SELECTOR SWITCH AND TRANSFER SWITCH UNIT FOR TAPPED REGULATINGTRANSFORMERS Filed July 2, 1963 s Sheets-Sheet 1 Wmwrop AlexunderBleibtreu by Atty- Feb. 1, 1966 A. BLEIBTREU 3,233,049

INTEGRAL SELECTOR SWITCH AND TRANSFER SWITCH UNIT FOR TAPPED REGULATINGTRANSFORMERS Filed July 2, 1963 Sheets-Sheet 2 53 l 2,7 I 48 F/GE 28 58so i I: 62 52 T 30 63 l 47! se ll F 47 i 43 I '2 73 64 /l r I 4| l I t65C 72L I 72 i 65b? j I j H g 65c 77 Iii l e7 67 1F 1F 66 I so 27 66 3938 74 Q I F 9| 6 i I .i s H & 1 1 O I V o 34 l 22 I 1 g I s l 7 220 j 37I I J flvmwroq:

Alexund er Bleibtreu 23 I8 230 33 M X by Atty.

Feb. 1, 1966 .BLEIBTREU 3,233,049

INTEGRAL SELEC SWITCH AND TRANSFER SWITCH T FOR UNI TAPPED REGULATINGTRANSFORMERS Filed July 2, 1965 3 Sheets-Sheet 5 & i

Alexander Bleibtreu by An;

United States Patent Ofi ice 3,233,049 INTEGRAL SELECTOR SWITCH ANDTRANSFER SWITCH UNIT FOR TAPPED REGULATING TRANSFORMERS AlexanderBleibtreu, Regensburg, Germany, assignor to Maschinenfabrik ReinhausenGebriider Scheubeck K.G., Regensburg, Germany Filed July 2, 1963, Ser.No. 292,353 Claims priority, application Germany, July 12, 1962, M53,532 11 Claims. (Cl. 200-11) This invention relates to tap-changingregulating transformers, i.e. transformers including one or more tappedwindings which make it possible to regulate the voltage of thetransformer. I

Tap-changing regulating transformers include selector switches andtransfer switches. The former serve the purpose of selecting any desiredtap along a tapped transformer winding intended to be connected into anelectric circuit. Selector switches are not required to interruptcurrent-carrying circuits, or to close on current carrying circuits.These two tasks are assigned to and performed by the transfer switches,i.e. the latter perform all switching operations under load.

The taps of tapped transformer windings are conductively connected tothe selector switches. The selector switches are, in turn, conductivelyconnected to the trans fer switches. As a result, tap-changingregulating transformers comprise complex systems of leads between theselector switches and the transfer switches. Since selector switches andtransfer switches are generally arranged in different tanks or housings,and since the tanks or housings of transfer switches are generallyfilled with oil, it is necessary to provide a large number ,of oil tightbushings to conductively interconnect selector switches and the transferswitches.

It is, therefore, one object of the invention to provide switchingsystems for tap-changing regulating transformers including coordinatedand integrated selector switches and transfer switches which systemshave simple conductive means for the interconnection of selectorswitches and their transfer switches.

It is another object of the invention to provide switching systems fortap-changing regulating transformers comprising selector switches andtransfer switches which systems form compact structural units that canreadily be assembled and disassembled with a minimum of labor and with aminimum of tooling.

Another object of this invention is to provide integral selector switchand transfer switch structures which are constructed substantiallysymmetrically around a central axis of symmetry and which structureshave conductive means arranged substantially along said axis of symmetryfor conductively interconnecting its two constituent switch 7 units.

Still another object of the invention is to provide switching systemsfor tap-changing regulating transformers dispensing with the complexsystems of leads or wiring normally found in such switching systems.

Still another object of the invention is to provide switching systemsfor tap-changing regulating transformers wherein the conductiveconnections between the selector switches and the transfer switches areshielded and encapsulated and out of the way when access to the same isnot needed such as, for instance, when the arcing contacts of thetransfer switches are being checked by maintenance personnel and whenthere is no need to inspect the electrical connections between theselector switches and the transfer switches, these connections beingsubjected to a minimum of wear and tear.

The above objects and additional objects and advantages of the inventionwill become more apparentfrom 3,233,049 Patented Feb. 1, 1966 theensuing description of the invention, and of a specific embodimentthereof, when read in connection with the accompanying drawings.

Referring now to the drawings:

FIG. 1 is a diagrammatic representation of a switching system for atap-changing regulating transformer embodying the present invention;

FIG. 2 is a vertical section taken along 11 of FIG. 3 and shows a systemof the kind shown diagrammatically in FIG. 1 and includes the essentialstructural details of such a system;

FIG. 3 is a section along.3-3 of FIG. 2; and

FIG. 4 is a section along 4-4 of FIG. 2.

Generally tap-changing regulating transformers comprise three phases andwindings for each of the three phases. The tapped winding of each phaseis operatively related to a selector switch and to a transfer switch. Atap-changing regulating transformer having three tapped windingscomprises therefore three selector switches, one for each tappedwinding, and three transfer switches, each transfer switch beingconnected to one of the three selector switches and each transfer switchswitching one phase of the three phase circuit. FIG. 1 shows a tappedtransformer winding T pertaining to one phase of a three phasetransformer which is Y-connected. The letter Y has been applied toindicate the neutral point of the system and the letter U has beenapplied in FIG. 1 to indicate that the winding T is a phase winding of apolyphase system U, V, W. Winding T, is provided with a number of tapsconsecutively numbered 1 to 16. Reference character S has been appliedto generally indicate a selector switch connected to the taps oftransformer winding T, and reference character T has been applied togenerally indicate a transfer switch conductively connected to selectorswitch S. One terminal of transfer switch T is conductively connected tothe neutral point Y of the system. Selector switch S comprises a hollowvertical column 17 of insulating material and a plurality of fixed tapcontacts to which reference characters 1 to 16 have been applied. Fixedtap contact 1 is conductively connected bylead 1" to tap 1, fixed tapcontact 2' is conductively connected by lead 2" to tap 2, etc., andfixed tap contact 15 is conductively connected by lead 15 to tap 15, andfixed tap contact 16 is conductively connected by lead 16" to tap. 16.No reference characters have been applied in FIG. 1 to taps 3 to 14,inclusive, the numbering of these taps being obvious. Taps 3 to 14,inclusive, are connected by leads to the fixed tap contacts to which thesame reference character has been applied with the addition of a prime.The leads conductively connecting taps 3 to 14 to tap contacts 3' to 14'have only been shown in part in FIG. 1 in order not to encumber thisfigure with an excess of lines. All odd numbered tap contacts 1' to 15'of selector switch S are arranged in a circular pattern on a relativelyhigh level and all even numbered tap contacts 2 to 16 of selector switchS are arranged in a circular pattern on a relatively low level. Contacts1' to 16' may be arranged in a cylindrical surface indicated in FIG. 1by two ellipses to which reference character F has been applied.Selector switch S further comprises an upper fixed circular or annularslide contact 18 and a lower fixed circular or annular slide contact 19.The two contact arms or contact bridges 20 and 21 are pivotable aboutthe vertical geometrical axis of column 17. To be more specific, theupper bridge 20 adapted to selectively interconnect any of the oddnumbered tap contacts 1' to 15' and annular slide contact 18 has as itsfulcrum the point of intersection of the axis of column 17 with theplane of the upper horizontal ellipse F, and the lower bridge 21 adaptedto selectively interconnect any of the even numbered taps 3 the point ofintersection of the axis of column 17 with the plane of the lowerhorizontal ellipse F. Each arm or bridge 20 and 21 may be pivoted aboutits respective fulcrum by appropriate operating means not shown in FIG.1 and described below in connection with FIG. 2. Annular contact 18 isconductively connected to a current-carrying rod 22 extending inadirection longitudinally of column 17 and ending above in a plug contact24 adapted to cooperatively engage a female or socket contact 26 formingpart of transfer switch T. In like fashion annular contact 19 isconductively connected to a currentcarrying rod 23 extending in adirection longitudinally of column 17 and ending above in a plug contact25 adapted to cooperatively engage a socket contact 27 forming part oftransfer switch T.

Transfer switch T comprises a pair of movable main contact bridges 28each adapted to conductively interconnect a pair of fixed main contacts30 and to part from such a pair of main contacts 30. Transfer switch Tfurther comprises a pair of movable auxiliary contact bridges 29 eachadapted to conductively interconnect a pair of fixed auxiliary contacts31 and to part from such a pair of auxiliary contacts 31. All fixedcontacts 30 and'31 of I transfer switch T are arranged in a cylindricalsurface and all contact bridges 28 and 29 of transfer switch T areadapted to be moved selectively radially inwardly out of engagement witha cooperating pair of fixed contacts and 31, respectively, or radiallyoutwardly into engagement with a pair of cooperating fixed contacts 30and 31, respectively.

All the upper fixed contacts 30, 31 of transfer switch T areconductively connected to the neutral point Y of the electric system.Transfer switch T further comprises a pair of switch-over resistors 32hav- 7 ing upper ends each connected to one of the lower pair of fixedauxiliary contacts 31. The lower ends of switching or switch-overresistors 32 and the lower pair of fixed main contacts 30 areconductively connected to female contacts or sockets 26 and 27,respectively, cooperatively engaged by plugs 24 and 25, respectively.

In the position of the parts shown in FIG. 1 the following circuit isestablished: Tap 6, tap contact 6', bridge 21, annular or ring contact19, rod 23, plug 25, socket 27, left lower contact 30, left contactbridge 28, left upper contact 30, neutral point Y. Hence tap 6 iseffective and all the other taps of the tapped winding T areineffective.

the contact bridges 28 and 29 of transfer switch T. The

first step consists in engagement of left auxiliary contacts 31 by leftauxiliary contact bridge 29. The second step consists in engagement ofthe right auxiliary contacts 31 by right auxiliary contact bridge 29.Thereupon the left main contact bridge 28 parts from its cooperatingfixed main contacts 30. Since the right resistor 32 is connected to tap15 by the intermediary of contacts 26, 24, rod 22 and contacts 18, 2t)and 5, the closing operation of right auxiliary bridge contact givesrise to a circulating current. This circulating current is superimposedupon the load current and must be interrupted by the operation oftransfer switch T. Parting of left main bridge contact 28 from its fixedmain contacts 30 is followed by engagement of right fixed main contacts30 by their cooperating right main bridge contact 28. Thereupon left Iauxiliary contact bridge 29 parts from the left auxiliary contacts 31,thus interrupting the above referred to circulating current. Finallyright auxiliary bridge 29 may part from its cooperating fixed contacts31.

FIG. 1 illustrates a so-called pennant transfer switch or brieflyP-transfer switch. The gist of pennant transv fer switches of P-transferswitches resides in the fact that prior to interrupting a circuitincluding a given tap of a tapped transformer winding, anotherpre-selected tap-in the instant case tap 5is being connected into thecircuit by the intermediary of an ohmic resistor. A pennant invention.Other types of transfer switches may be substituted for the pennanttransfer switch shown in FIG. 1. Other kinds of transfer switches whichmay readily take the place of the pennant transfer switch shown in FIG.1 have been described in the copending patent application of AlexanderBleibtreu, filed January 31, 1963, Ser. No. 255,291, now Patent No.3,174,097, for Transfer Switch for Tap Changers for RegulatingTransformers, and reference may be had to that application for furtherdetails regarding other transfer switches which may take the place ofthe particular transfer switch T shown in FIG. 1.

Assuming now that it is intended to move from tap 6the tap shown to beeffective in FIG. 1-to tap 7 rather than to the lower tap 5. This isachieved by pivoting arm 20 in clockwise direction as seen in FIG. 1from tap contact 5 to tap contact 7' while leaving arm or bridge 21 ofselector switch S at rest on tap contact 6. As a result, tap contact 7is conductively connected to the lower right fixed main contact 31 oftransfer switch T by the intermediary of rod 22 and cooperating plug andsocket contacts 24 and 26. Subsequent operation of transfer switch T inthe fashion which has been described above results in disconnectingneutral point Y from tap 6 and connecting that point to tap 7.

' In FIGS. 24 the same reference characters as in FIG. 1 have beenapplied to indicate like parts. FIG. 2 shows, in part, three transferswitches and three selector switches, one switch for each phase of athree phase circuit, but the parts pertaining to two of the three phaseshave been largely omitted in FIG.' 2 in the same general fashion as inFIG. 1'. In FIG. 2 reference character S has been applied to generallyindicate a selector switch, reference character T has been applied togenerally indicate a transfer switch arranged above selector switch S,and reference character 32 has been applied to generally indicate aplurality of switch-over resistors arranged above the selector switch Sbut below the transfer switch T. As shown in connection with FIG. 1 thecontact arms or contact bridges of the selector switch S must beoperated alternately, i.e. while one of the arms is moved from one ofthe fixed tap contacts the other arm remains at rest, and vice versa.Such a movement could be effected manually, but is preferably effectedby means of an appropriate Geneva gear drive. Reference character G hasbeen applied to generally indicate the housing of a Geneva gear drivefor operating the selector switch S arranged below the Geneva geardrive.

'The selector switch S comprises a vertical column 17 of insulatingmaterial housing a plurality of vertical currentcarrying rods. FIG. 2shows two of these rods to which reference numerals 22 and 23 have beenapplied and FIG. 3 shows three pairs of such rods, one for each phase ofa three phase circuit. The two rods 22, 23 shown in FIG. 2 pertain toone phase of a three phase circuit, as explained in connection withFIG. 1. A three phase selector switch and transfer switch systemtherefor comprises a total of six current carrying rods as clearly shownin FIG. 3. The lower end of current-carrying rod 22 is inserted into aterminal 33. The latter is conductively connected to fixed annular slidecontact 18 which is adapted to be engaged by a contact bridge pivotableabout the axis of column 17 and having a radially outer end adapted toselectively engage any'of a group of fixed tap contacts in the fashionshown in FIG. 1 and described in connection with that figure. Thecontact bridge 20 (see FIG. 1) engaging annular contact 18 may beoperated by 34, and reference numeral 15' has been applied to that fixedtap contact for indicating the latter. The vertical current-carrying rod23 is conductively connected to a lower annular contact not shown inFIG. 2 but shown in FIG. 1 and designated therein by the referencenumeral 19 and in operative engagement with a contact bridge 21. Thecontact bridge 21 of FIG. 1 is operated by the vertical insulating rod37 of FIG. 2 which, in turn, is operated by gear 38 arranged in gearhousing G. Other details of selector switch S are preferably designed inaccordance with the disclosure made in the copending patent applicationof Alexander Bleibtreu, filed December 13, l962, Ser. No. 246,289 forSelector Switch for Tapped Regulating Transformers and reference may behad to this application for such details. The upper end of insulatingcolumn 17 is closed by a closing member 39 of metal and rods 22 and 23project from the inside of column 17 transversely through closing member39 to the outside of column 17. To this end rods 22 and 23 are wrappedin insulating material, i.e. they are surrounded by tubular insulators22a, 234 which form bushings jointly with rods 22 and 23.

The transfer switch T of FIG. 2 comprises four movable bridge contactscorresponding to contacts 28 and 23 of FIG. 1. FIG. 2 shows but one ofthese bridge contacts to which reference character 28 has been applied.Contact bridge 28 is adapted to be moved radially outward intoengagement with a pair of fixed contacts 30 or radially inward out ofengagement with fixed contacts 30.

The three phase transfer switch T shown in FIGS. 2-4 further comprises acylindrical tank accommodating a coaxial supporting structure. Thatstructure includes a bottom frame member 41, a top frame member 42 and aplurality of vertical rods or bars 43 of insulating material. The latterare angularly displaced and spaced and supported by frame members 41.42. Thus parts 41, 42, 43 form a squirrel cage structure. Tank 40 maycontain, and will normally contain, a body of oil (not shown). Terminal44 is integral with tank 1 which may be made of a appropriate insulatingmaterial. This terminal is intended to connect the transfer switch tothe neutral point of the regulating transformer indicated by referencecharacter Y. i If tank 1 is made of a casting resin terminal 44 of thetransfer switch T may be in the form of an insert in the casting asshown in the upper left corner of FIG. 2.

Top frame member 42 is made of metal and provided with contactscooperatively engaging with terminal 44.

A structure substantially in the shape of a second radially innersquirrel-cage is suspended on frame member 42 by means of screws 45. Theabove mentioned second structure substantially in the shape of asquirrel-cage comprises the upper plate member 46, the lower platemember 47 and three conductive vertical bars 48 extending parallel tothe common axis of tank 1 and first squirrel-cage structures 41, 42, 43.Bars 48of which but one is shown in FIG. 2-enclose angles of 360/ 3:120degrees. The upper end plate 53 and the lower end plate are fixedlymounted upon, and pivotable jointly with, operating shaft 49 for contactbridges 28, 29, which shaft rests in bearings 50, 51. Shaft 49 isarranged in coaxial relation to tank 4%) and to insulating column 17 andto squirrel-cage structures 41, 42, 43 and 46, 47, 48, respectively.Rods 52-of which but one is shown in FIG. 2 and of which one is providedfor each phaseare spaced from shaft 49 and extend parallel to shaft 49.The upper ends and the lower ends of rods 52 are loosely guided by theupper end plate 53 and the lower end plate 55, respectively. The upperends of rods 52 are mechanically tied to the upper end plate 53 by meansof helical tension springs 54 of which but one is shown in FIG. 2. Inlike fashion the lower ends of rods 52 are mechanically tied to thelower end plate 55 by means of helical tension springs 56 of which butone has been shown in FIG. 2. Reference numeral 57 has been applied toindicate a plurality of upper contact operating arms and referencenumeral 58 has been applied to indicate a plurality of .lower contactoperating arms. Each contact operating L arm 57, 58 has. a radiallyinner bearing 59 and a radially outer bearing 60. Rods 59 extend throughthe radially inner bearings 59 of contact operating arms 57, 58. Thebearings 60 on the radially outer ends of each pair of contact operatingarms 57, 58 support a vertical rod 61 which, in turn, pivotally supportsa contact carrier 62. Contact carriers 62 insulatingly support theaforementioned contact bridges 28 and 29 extending parallel to operatingshaft 49 of which but one is shown in FIG. 2. The aforementioned upperand lower plate members 46, 47 are provided with radially extendingslots or grooves 46, 47, respectively, engaged by and guiding the upperand the lower ends of contact carriers 62. Because of this function ofplate members 46, 47 the same may be referred-to as guide plates.

As mentioned above the upper end of each contact bridge 28, 29 and thelower end of each contact bridge 28, 29 are adapted to cooperate with apair of fixed contacts 3t) and 31, respectively of which but one pair 30is shown in FIG. 2. Each pair of fixed contacts 30, 31 is supported byone of the aforementioned vertical bars 43 forming part of squirrel-cagestructure 41, 42, 43. As mentioned above, bars 43 are made of anappropriate insulating material and they are preferably H-shaped incross-section. Thus each bar 43 defines a radially inner channel-shapedspace and a radially outer channel-shaped space. Contacts 38, 31 areaccommodated in the radially inner channel-shaped spaces defined by bars43. Contacts 3t), 31 are supported in position on bars 43 by means ofscrews 63, or equivalent fasteners. As shown in FIG. 2 the heads ofthese screws 63 are located in the radially outer channel spaces definedby rods or bars 43. Therefore the heads of the screws 63 supportingfixed contacts 30, 31 are readily accessible from the outside ofradially outer cage structure 41, 42, 43. The same applies as to screws64, or equivalent fasteners, securing insulating bars 43 to parts 41 and42.

The circuitry of FIG. 1 calls for the provision of four contact carriers62 and of four contact bridges 28, 29

and of four pairs of fixed contacts 30, 31 per phase. In otherapplications the number of contact carriers, contact bridges and ofpairs of fixed contacts per phase may be smaller than four, or largerthan four. Thus the structure of FIG. 2 may include six pairs of fixedcontacts and six movable contact bridges per phase.

The current path of the. transfer switch T of FIG. 2 is substantiallythe same as explained in connection with FIG. 1. The current pathextends through lower fixed arcing contacts 30, contact bridges 28 andupper fixed contacts 30. Upper fixed contacts 30 are conductivelyconnected by leads not shown in FIG. 2 to element 42 which, in turn, isconductively connected to the neutral point Y of the three phase systemby the intermediary of terminal 44.

The kinematic theory underlying the structure of FIG. 2 is set forth indetail in United States Patent 2,680,790 to Bernhard Jansen, June 8,1954 for Load Changeover Swith for Tapped Transformers Usingacombination of Contact Movements and reference may be had to thatpatent for additional information regarding this subject. The operationof the structure of FIG. 2 is briefly as follows: Pivotal movement ofoperating shaft 49 results in pivotal or rotary motions of end plates53, 55 transmitted to rod or shafts 52. The pivotal motion of rods orshafts 52 about the vertical axis of transfer switch T causes movementof contact carriers 62 relative to guide plates 46, 47, the upper andlower ends of contact carriers 62 sliding in grooves 46, 47 of guideplates 46, 47. As a result, contact bridges 28 and 29, respectively, aremoved in the proper sequence radially either outwardly into engagementwith fixed contacts 30, 31, or inwardly out of engagement with thesefixed contacts. I

It will be apparent from the foregoing that transfer switch T andselector switch S dispense entirely with .fiexible connections, orbraids, for connecting the movable contact bridges 28 and 29 to annularcontacts 18, 19;.

Since contact bridges 28, 29 are insulated from their supports 62 allthe movable parts within the transfer switch T may be made of metalrather than of insulating material which greatly contributes to theruggedness of transfer switch T. The ruggedness of transfer switch T isdue in particular to the presence of the squirrel-cage type structurecomprising guide plates 46, 47 and the three conductive squirrel-cagebars 48.

Though the double break feature embodied in the structure of FIGS. 1 and2 greatly increases the life of the cooperating pairs of contacts 28, 30and 29, 31, respectively, it is of great importance to be able toreadily obtain access to all parts of the switch which are subjected towear and tear. Heretofore the inspection and/ or replacement of theradially outer fixed contacts was a relatively difiicult task, requiringa radially inward retraction of the contact bridges and their supportingstructures. Performance of this task calls for special tools and highlyskilled labor. The structure of FIGS. 1-4 greatly facilitates inspectionand/or replacement of fixed contacts 30, 31. All that is required tothis end is removal of the contact supporting insulating bars 43 fromparts 41 and 43. This can readily be achieved since the heads ofbarsupporting screws 64 are arranged on the radially outer surfaces ofbars 43.

Bearing 51 for operating shaft 49 is arranged on a hearing support 65bwhich, in turn, is supported by insulating member 41 forming part of theaforementioned cage 41, 42, 43. Insulating cylinder 65 is arranged incoaxial relation to insulating tank 40 and insulating column 17 ofswitch S and further arranged below part 41 and bearing support 65b.Cylinder 65 is suspended by means of screws 65a from parts 41, 65b andarranged in the lower portion of insulating tank 40 not occupied bytransfer switch T. The vertical duct 65c defined by insulating cylinder65 accommodates a plurality of pairs of female contacts 26, 27 eachcooperatively engaged by the bare upper ends 24 and of contact rods 22and 23, respectively.

FIG. 4 shows more in detail the plug-in contact means for conductivelyconnecting selector switch S and transfer switch T. In FIGS. 2 and 4reference character 66 has been applied to indicate means defining ductsfor guiding the bare upper ends 24, 25 of conductor rods 22, 23. Thefemale contact means 26, 27 include superimposed pairs of spring biasedhorizontal finger contacts 67 hugglng rod contacts or plug contacts 24,25. Female contact means 26, 27 further comprise a base 68 supported byinsulating cylinder 65 on the inside thereof. Current is conducted fromfinger contacts 67 to base 68 through the intermediary of flexibleconductors or braids 70. The upper ends of bases 68 form terminals forleads 69 (FIG. 2) included in the current paths from selector switch Sto transfer switch T. The upper side of insulating cylinder 65 defines apair of slots '72 each for the passage of one of the pair of leads 69from the inside of insulating cylinder 65 to the outside thereof.Transfer switch T may be provided, in addition to the arcing contactsshown in FIG. 1 and described in connection therewith, with cooperatingpairs of relatively movable current-carrying contacts. Such contacts aredesigned to shunt the main arcing contacts 28, of FIG. 1. Leads 69 maybe connected to the fixed current-carrying contacts of which one hasbeen shown in FIG. 2 and indicated therein by reference numeral 73. Fora more detailed disclosure of the arrangement of current-carryingcontacts in a transfer switch of the kind shown in FIGS. 1 and 2 anddescribed in connection therewith reference may be had to theaforementioned copending patent application of Alexander Bleibtreu,filed January 31, 1963, Ser. No. 255,291 for Transfer Switch for TapChangers for Regulating Transformers.

der 65 supports a pair ofparallel spaced insulating plates- 74, formingsupports for the switching resistors generally indicated by referencecharacter 32. Numeral 76 has been applied to indicate rods having endsprojecting into registering holes in plates 74 and '75. Thus rods 76 arefirmly held in position by plates 74 and 75. Rods 76 surround insulatingcylinder 65in form of two concentric shells as clearly shown in FIG. 3.Mounted on each rod 76 is a tubular core 77, preferably made of aceramic insulating material, and wound around cores 77 are resistancewires 73 to be used as switch-over resistors. Radially extendingpartitions 79 sub-divide the aforementioned switch-over resistors intogroups of five, each such group being substantially in the shape of asector of a cylinder ring.

Gears 36 and 38 in housing G of FIG. 2 are Geneva gears operated from avertical shaft 80 by the intermediary of crank shaft 51. Crank shaft 91is provided with driving pins adapted to engage the slots formed byGeneva gears 36, 38 and the alternate operation of gears 36, 38,operating rods 34, 37- and the contact bridges 20, 21 operated by theserods is due to the angular displacement of the aforementioned drivingpins on crankshaft 91. Such Geneva gear drives for alternate operationof the movable contacts of selector switches are generally known in theart and, therefore, need not be described in detail in this context. AGeneva gear drive of this general character has been disclosed in detailin the copending patent application of Alexander Bliebtreu, filed June18, 1963, Ser. No. 288,- 636, for Improvements in RegulatingTransformers, and reference may be had to this application for furtherdetails on Geneva gear drives for achieving alternate operation of themovable contacts of selector switches.

The entire switching system T, G, S, is intended to be placed in thetransformer tank, i.e. the tank housing the transformer whose circuitryis controlled by the switching system T, G, S.

It will be apparent from the foregoing that the electrical connectionsbetween selector switch S and transfer switch T are centrally locatedand do not encumber the switching system T, G, S and are not in the wayof service and repair personnel. The transfer switch T may be lifted asa unit out of insulating tubing or insulating case 40, resultingautomatically in a separation of male contacts 24, 25 from femalecontacts 26, 27. This makes for a very simple disassembly of theswitching system T, G, S, and vice versa, a very simple assemblythereof.

Although I have shown and described in considerable detail a specificstructure embodying my invention, it is to be clearly understood thatthe same was merely for the purpose of illustration, and that changesmay be made by those skilled in the art without departing from thespirit and scope of the invention as defined in the following claims.

I claim as my invention:

1. A switching system for tap-changing regulating transformerscomprising in combination:

(a) a selector switch having a hollow centrally arranged insulatingcolumn supporting on the outside thereof a pair of annular fixedcontacts, tap contacts circularly arranged around each of said pair ofannular contacts and pivotable contact arms for conductively connectingeach of said tap contacts to one of said pair of annular contacts;

(b) a transfer switch inside of a cylindrical housing arranged abovesaid selector switch, said transfer switch having circularly arrangedfixed contacts, cooperating radially movable contacts, contact operatingmeans for causing relative movement of said fixed contacts and saidmovable contacts in a predetermined sequence, an operating shaft foroperating said movable contacts extending along the axis of saidhousing, and said transfer switch further including a fixed framestructure inside said housingsupporting said fixed contacts, saidmovable contacts and said contact-operating means;

(c) means of insulating material defining a vertical duct, said ductdefining means being arranged inside of said housing in coaxial relationthereto and below said fixed contacts, movable contacts and saidcontact-operating means of said transfer switch and integral with saidfixed frame structure thereof;

(d) closing means for the upper end of said insulating column of saidselector switch; and

(e) means conductively connecting said pair of annular contacts of saidselector switch and said fixed contacts of said transfer switch, saidconnecting 'means including plug contact means having ends inside ofsaid insulating column and projecting upwardly across said closing meansinto said duct, and said connecting means further including socketcontact means arranged inside said duct, supported by said duct definingmeans and cooperatively engaged by said plug contact means.

2. A switching system for tap-changing regulating transformerscomprising in combination:

(a) a selector switch having a centrally arranged hollow insulatingcolumn, annular radially inner fixed contact means arranged'immediatelyadjacent said column in axial relation thereto, radially outer fixed tapcontact means circularly arranged around said column, rotatable contactarms for conductively connecting said tap contact means and said annularcontact means, and said selector switch further including means forclosing the upper end of said column;

(b) a transfer switch inside of a cylindrical housing arranged abovesaid selector switch in coaxial relation to said insulating columnthereof, said transfer switch having circularly arranged fixed contacts,radially movable contacts cooperating with said fixed contacts andcontact-operating means for causing relative movement between said fixedcontacts and said movable contact in a predetermined sequence, saidtransfer switch further having a fixed frame structure supporting saidfixed contacts, said movable contacts and said contact-operating meansand said transfer switch further including an operating shaft for saidcontact operating means extending along the axis of said housing;

(c) means of insulating material defining a vertical duct, saidduct-defining means being arranged inside said housing of said transferswitch in coaxial relation thereto below said transfer switch andintegral with said fixed frame structure thereof; and

(d) means conductively interconnecting said annular fixed contacts ofsaid selector switch to said transfer switch, said interconnecting meansincluding bushings supported by said closing means for the upper end ofsaid column, said bushings including vertical rods projecting, from theinside of said column transversely through said closing means to theoutside of said column, and said interconnecting means further includingfemale contacts arranged in said vertical duct, supported by saidduct-defining means and cooperatively engaged by the upper ends of saidrods. 7

3. A switching system for tap-changing regulating transformerscomprising in combination:

(a) a rotary selector switch including a plurality of circularlyarranged tap contacts, a hollow insulating column arranged coaxially tosaid plurality of tap contacts and terminals situated inside of saidcolumn for connecting said selector switch to a transfer switch;

(b) a cylindrical housing arranged above said column in coaxial relationthereto;

(c) a transfer switch arranged inside said housing occupying but theupper portion thereof, said transfer switch including circularlyarranged fixed contacts, radially movable contacts cooperating with saidfixed contacts and contact-operating means for causing engagement anddisengagement of said fixed contact and said movable contacts in apredetermined sequence, said transfer switch further including a drivingshaft for said contact-operating means arranged in coaxial relation tosaid column and to said housing;

(d) means of insulating material defining a vertical duct coaxial tosaid column, said duct-defining means occupying but the lower portion ofsaid housing and separating said duct from a radially outer space ofsaid lower portion of said housing;

(e) a plurality of current-limiting switching resistors to be insertedinto the current path leading from said selector switch to said transferswitch during a switching operation of said transfer switch arrangedinside said radially outer space of said lower portion of said housing;

(f) closing means for the upper end of said insulating column of saidselector switch; and

(g) means for conductively connecting said selector switch terminals tosaid transfer switch and said switching resistors, said connecting meansincluding a plurality of electrically insulated vertical rods extendingfrom the inside of said column across said means into said duct, andsaid connecting means further including a plurality of female contactsarranged inside said duct, supported by said duct-defining means andeach cooperatively engaged by the upper end of one of said plurality ofrods.

4. A switching system for tap-changing regulating transformerscomprising in combination:

(a) a rotary type selector switch including a central verticalinsulating column having a closing structure at the upper end thereofand having radially outer tap contacts and radially inner annularcontacts arranged around said insulating column in coaxial relationthereto, said selector switch further including radially extendingpivotable contact arms for conductively connecting said tap contacts andsaid radially inner annular contacts;

(b) a plurality of bushings projecting transversely through said closingstructure each having an inner conductor conductively connected with thelower end thereof to one of said radially inner annular contacts;

(c) a rotary type transfer switch having a frame structure supportingall the contact making and the contact breaking parts thereof andincluding an operating shaft arranged above said selector switch incoaxial relation to said insulating column thereof;

((1) a tubular insulating structure depending from said frame structureof said transfer switch and arranged above said selector switch incoaxial relation to said insulating column thereof;

(e) means for conductively interconnecting said selector switch and saidtransfer switch, said interconnecting means including a plurality offemale contact structures placed inside of and supported by 'saidcylindrical insulating structure and circularly arranged around thecommon axis of said insulating column of said selector switch and ofsaid transfer switch; and

(f) the upper end of said inner conductor of each of said plurality ofbushings forming a plug contact cooperatively engaging one of saidplurality of female contact structures.

5. A switching system for tap-changing regulating transformerscomprising in combination:

(a) a rotary type selector switch including a central verticalinsulating column having a closing structure at the upper end thereofand having radially outer tap contacts and radially inner annularcontacts arranged around said insulating column in coaxial relationthereto, said selector switch further including radially extendingpivotable contact arms for conductively connecting said tape contactsand said radially inner annular contacts;

(b) a plurality of bushings projecting transversely through said closingstructure each having an inner conductor rod conductively connected withthe lower end thereof to one of said radially inner annular contacts;

(c) a rotary type transfer switch having a frame structure supportingall the contact making and contact breaking parts thereof and includingan operating shaft arranged above said selector switch in coaxialrelation to said insulating column thereof;

((1) a tubular insulating structure depending from said frame structureof said tnansfer switch and arranged above said selector switch incoaxial relation to said insulating column thereof;

(e) a plurality of interconnecting structures placed inside of andsupported by said tubular insulating structure and arranged circularlyaround the axis thereof, each of said plurality of interconnectingstructures including a radially inner portion in the form of a femalecontact and a radially outer portion in the form of a terminal for alead connecting said female contact to a point of said transfer switch;and

(f) the upper end of said conductor rod of each of said plurality ofbushings forming a plug contact cooperatively engaging said femalecontact of one of said plurality of interconnecting structures.

6. A switching system for tap-changing regulating transformerscomprising in combination:

(a) a rotary type selector switch including a central vetricalinsulating column having a closing structure at the upper end thereofand having radially outer tap contacts and radially inner annularcontacts arranged around said insulating column in coaxial relationthereto, said selector switch further including radially extendingpivotable contact arms for conductively connecting said tap contacts andsaid radially inner annular contacts;

a (b) a plurality of bushings projecting transversely through saidclosing structure each having an inner conductor conductively connectedwith the lower end thereof to one of said radially inner annularcontacts;

(c) a rotary type transfer switch having a frame structure supportingall the contact making and the contact breaking parts thereof andincluding an operating shaft arranged above said selector switch incoaxial relation to said insulating column thereof;

(d) an insulating structure depending from said frame structure of saidtransfer switch and defining a vertical duct having a longitudinal axis,said insulating structure being arranged above said selector switch incoaxial relation to said insulating column thereof;

(e) means for conductively interconnecting said selector switch and saidtransfer switch, said interconnecting means including a plurality ofcontact structures placed inside said duct and supported by saidinsulating structure and circularly arranged around said longitudinalaxis of said duct; and

(f) the upper end of said inner conductor of each i of said plurality ofbushings forming a plug contact cooperatively engaging one of saidplurality of contact structures.

7. A switching system as specified in claim 6 wherein said insulatingstructure supports current-limiting switchover resistors conductivelyconnected to said transfer switch to be inserted during switchingoperations of said transfer switch into current paths including saidinner conductor of each of said plurality of bushings.

8. A switching system as specified in claim 6 wherein said insulatingstructure supports a pair of spaced horizontal insulating plates andwherein said insulating plates support current-limiting wire switch-overresistors conductively connected to said transfer switch to be insertedduring switching operations of said transfer switch into current pathsincluding said inner conductor of each of said plurality of bushings,said resistors being arranged in substantially concentric shells aroundsaid insulating structure.

9. A switching system for tap-changing regulating transformerscomprising in combination:

(a) a transfer switch including a cylindrical container,

a plurality of pairs of superimposed registering fixed contacts arrangedin a cylindrical surface coaxial with and spaced from said container, aplurality of sequentially operable vertical contact bridges each adaptedto be moved radially outwardly inside of said container and to be movedradially inwardly inside of said container to engage one of saidplurality of pairs of fixed contacts and to part from one of saidplurality of pairs of fixed contacts, operating means for said contactbridges comprising a vertical shaft, and a frame structure forsupporting said fixed contacts, said contact bridges and said operatingmeans thereof;

(b) an insulating structure defining a vertical duct depending from saidframe structure of said transfer switch and arranged in coaxial relationto said cylindrical container thereof;

(c) a rotary type selector switch operatively related to said transferswitch and arranged below said insulating structure, said selectorswitch including a central vertical insulating column having a closingstructure at the upper end thereof and having radially outer tapcontacts and radially inner annular contacts arranged around saidinsulating column in coaxial relation thereto, said selector switchfurther including radially extending pivotable contact arms forconductively connecting said tap contacts and said radially innerannular contacts;

((1) a plurality of bushings projecting transversely through saidclosing structure each having an inner conductor conductively connectedwith the lower end thereof to one of said radially inner annularcontacts and projecting with the upper end thereof into said verticalduct defined by said insulating structure; and

(e) means for conductively interconnecting said selector switch and saidtransfer switch, said interconnecting means including a plurality offemale contact structures placed inside said duct and supported by saidinsulating structure, each of said plurality of female contactstructures being cooperatively engaged by the upper end of said innerconductor of one of said plurality of bushings.

10. A switching system for tap-changing regulating transformerscomprising in combination:

(a) a selector switch including circularly arranged fixed tap contacts,a pair of fixed annular contacts arranged in coaxial relation to saidtap contacts and a pair of pivota'ble contact arms for selectivelyconnecting each of said tap contacts to one of said pair of annularcontacts;

(b) a transfer switch arranged above said selector switch and includingpairs of circularly arranged fixed contacts, radially movable contactbridges cooperating with said pairs of fixed contacts andcontact-operating means for sequentially operating said contact bridgesin a predetermined sequence;

(0) a frame structure supporting said pairs of fixed contacts, saidmovable contact bridges and said contact-operating means of saidtransfer switch;

(d) a cylindrical housing for said frame structure, said pair of fixedcontacts, said contact bridges and said contact-operating means arrangedin coaxial relation to said pair of annular contacts;

(e) a first tubular insulating member arranged inside said housing incoaxial relation thereto and integral with said frame structure;

(f) a second tubular insulating member arranged outside of said housingbelow said first insulating member in coaxial relation theretosupporting said pair of annular contacts of said selector switch;

(g) a closing structure for the upper end of said second insulatingmember; and

(h) means for conductively connecting said pair of annular contacts ofsaid selector switch to said pairs of fixed contacts of said transferswitch, said connecting means including bushings projecting across saidclosing structure for said upper end of said second insulating member,said bushings having internal conductor rods extending into said firstinsulating member, and said connecting means further includingcooperating male and female disconnect contacts arranged inside of saidfirst insulating member.

11. A switching system for tap-changing regulating transformerscomprising in combination:

(a) a selector switch including a plurality of circularly arranged tapcontacts, a pair of fixed annular contacts arranged in coaxial relationto said plurality of tap contacts and a pair of pivotable contact armsfor selectively connecting each of said plurality of tap contacts to oneof said pair of annular contacts;

(b) a transfer switch arranged above said selector switch and includingpairs of circularly arranged fixed contacts, radially movable contactbridges cooperating with said pairs of fixed contacts andcontact-operating means for sequentially operating said contact bridgesin a predetermined sequence;

(c) a frame structure supporting said pairs of fixed contacts, saidmovable contact bridges and said contact-operating means of saidtransfer switch;

(d) a cylindrical housing for said frame structure, said pairs of fixedcontacts, said contact bridges and said contact-operating means arrangedin coaxial relation to said pair of annular contacts of said selectorswitch;

(e) a first vertical tubular insulating member arranged inside saidhousing suspended (from said frame structure and open at the lower endthereof;

(f) a second vertical tubular insulating member arranged outside saidhousing below said first insulating member in coaxial relation theretosupporting said pair of annular contacts of said selector switch;

(g) means for closing said second insulating member at the upper endthereof;

(b) a pair of bushings projecting transversely across said closing meansand including a pair of contact rods each having a lower endconductively connected to one of said pair of annular contacts of saidselector switch and having an upper end projecting into said firsttubular insulating member; and

(i) a pair of female disconnect contacts conductively connected to saidpairs of fixed contacts of said transfer switch, arranged inside of saidfirst tubular insulating member and each engaged by said upper end ofone of said pair of contact rods.

References Cited by the Examiner UNITED STATES PATENTS 1,666,729 4/1928Biek et a1. 339196 1,935,163 11/1933 Parsons 338302 X 1,985,927 1/1935Jansen.

2,680,790 6/ 1954 Jansen 200--6 2,697,212 12/1954 Castelli 339l76 X3,020,518 2/1962 Camping et a1. 339191 3,034,542 5/1962 Blanco.

3,054,080 9/1962 Jepson 339196 X KATHLEEN H. CLAFFY, Primary Examiner.

ROBERT K. SCHAEFER, Examiner.

1. A SWITCHING SYSTEM FOR TAP-CHANGING REGULATING TRANSFORMERSCOMPRISING IN COMBINATION: (A) A SELECTOR SWITCH HAVING A HOLLOWCENTRALLY ARRANGES INSULATING COLUMN SUPPORTING ON THE OUTSIDE THEREOF APAIR OF ANNULAR FIXED CONTACTS, TAP CONTACTS CIRCULARLY ARRANGED AROUNDEACH OF SAID PAIR OF ANNULAR CONTACTS AND PIVOTABLE CONTACT ARMS FORCONDUCTIVELY CONNECTING EACH OF SAID TAP CONTACTS TO ONE OF SAID PAIR OFANNULAR CONTACTS; (B) A TRANSFER SWITCH INSIDE OF A CYLINDRICAL HOUSINGARRANGED ABOVE SAID SELECTOR SWITCH, SAID TRANSFER SWITCH HAVINGCIRCULARLY ARRANGED FIXED CONTACTS, COOPERATING RADIALLY MOVABLECONTACTS, CONTACT OPERATING MEANS FOR CAUSING RELATIVE MOVEMENT OF SAIDFIXED CONTACTS AND SAID MOVABLE CONTACTS IN A PREDETERMINED SEQUENCE, ANOPERATING SHAFT FOR OPERATING SAID MOVABLE CONTACTS EXTENDING ALONG THEAXIS OF SAID HOUSING, AND SAID TRANSFER SWITCH FURTHER INCLUDING A FIXEDFRAME STRUCTURE INSIDE SAID HOUSING SUPPORTING SAID FIXED CONTACTS, SAIDMOVABLE CONTACTS AND SAID CONTACT-OPERATING MEANS; (C) MEANS OFINSULATING MATERIAL DEFINING A VERTICAL DUCT, SAID DUCT DEFINING MEANSBEING ARRANGED IN SIDE OF SAID HOUSING IN COAXIAL RELATION THERETO ANDBELOW SAID FIXED CONTACTS, MOVABLE CONTACTS AND SAID CONTACT-OPERATINGMEANS OF SAID TRANSFER SWITCH AND INTEGRAL WITH SAID FIXED FRAMESTRUCTURE THEREOF; (D) CLOSING MEANS FOR THE UPPER END OF SAIDINSULATING COLUMN OF SAID SELECTOR SWITCH; AND (E) MEANS CONDUCTIVELYCONNECTING SAID PAIR OF ANNULAR CONTACTS OF SAID SELECTOR SWITCH ANDSAID FIXED CONTACTS OF SAID TRANSFER SWITCH, SAID CONNECTING MEANSINCLUDING PLUG CONTACT MEANS HAVING ENDS INSIDE OF SAID INSULATINGCOLUMN AND PROJECTING UPWARDLY ACROSS SAID CLOSING MEANS INTO SAID DUCT,AND SAID CONNECTING MEANS FURTHER INCLUDING SOCKET CONTACT MEANSARRANGED INSIDE SAID DUCT, SUPPORTED BY SAID DUCT DEFINING MEANS ANDCOOPERATIVELY ENGAGED BY SAID PLUG CONTACT MEANS.